Heat maps of the domain signature pairs associated with kinase-substrate interactions & ROC curves in cross-validation. Pairs of strings of domains (one on a kinase, the other on its substrate) that are statistically enriched (p < 0.001) in phosphorylation binding interactions in the learning set compared to the set of random pairs of proteins made up of proteins in the same set. The horizontal and vertical axes refer to indices of strings of domains enriched in kinases and kinase substrates, respectively. The scale - log p indicates the level of enrichment of the signature pairs shown in the figure 3A. The receiver operating characteristics (ROC) curves for 2-folds and 10-folds cross-validation (3B). The area under the ROC curves (AUC) is also shown for the ROC curves in the figure.